1. Technical Field
The present disclosure relates to power supply, and particularly to a power supply circuit for a CPU (central processing unit).
2. Description of Related Art
With the rapid development of personal computers, development of high performance components for computers has brought about a corresponding increase in power use. A CPU has a crucial effect on the stability of a computer. A power supply circuit is specially designed for providing power to the CPU.
Referring to FIG. 1, a commonly used power supply circuit for a CPU includes a PWM (pulse-width modulation) controller 50 which provides three pulse signals of, for example, phase 1, phase 2, and phase 3. Each of the three pulse signals turns a corresponding switch on or off at different times to provide multiphase power to the CPU. The PWM controller 50 is controlled by an I/O controller 40 also electrically coupled to a Southbridge chip 60. The Southbridge chip 60 provides a 3.3V DC voltage for the I/O controller 40 when the computer is powered off. However, the Southbridge chip 60 is grounded via the CPU and discharges to ground, which generates large amounts of leakage currents on the CPU whereby the computer cannot function.
Therefore, there is room for improvement within the art.